Method of manufacturing organic EL display unit and organic EL display unit

ABSTRACT

A method of manufacturing an organic EL display unit and an organic EL display unit capable of improving light emitting efficiency and life of blue are provided. A hole injection layer are formed on a lower electrode. For a red organic EL device and a green organic EL device, a hole transport layer, a red light emitting layer, and a green light emitting layer made of a polymer material are formed. A hole transport layer made of a low molecular material is formed on the hole injection layer of a blue organic EL device. A blue light emitting layer made of a low molecular material is formed on the red light emitting layer, the green light emitting layer, and the hole transport layer for the blue organic EL device. An electron transport layer, an electron injection layer, and an upper electrode are sequentially formed on the blue light emitting layer.

CROSS REFERENCES TO RELATED APPLICATIONS

The present application claims priority to Japanese Priority PatentApplication JP 2009-261354 filed in the Japan Patent Office on Nov. 16,2009, the entire content of which is hereby incorporated by reference.

BACKGROUND

The present application relates to a method of manufacturing an organicelectroluminescence (EL) display unit that emits light by using organicEL phenomenon and an organic EL display unit.

As development of information and communications industry has beenaccelerated, a display device having high performance has been demanded.Specially, as a next generation display device, an organic EL device hasattracted attentions. As a self light emitting type display device, theorganic EL device has an advantage that the view angle is wide and thecontrast is excellent. In addition, the organic EL device has anadvantage that the response time is short.

A light emitting layer and the like forming the organic EL device arebroadly classified into a low molecular material and a polymer material.In general, it is known that the low molecular material provides higherlight emitting efficiency and a longer life. In particular, the lowmolecular material provides a higher performance for blue.

Further, regarding a method of forming the organic film thereof, the lowmolecular material is formed by dry method such as a vacuum evaporationmethod, and the polymer material is formed by wet method such as spincoating, ink jet method, and nozzle coating.

The dry method has an advantage that a formation material of the organicthin film layer is not necessarily dissolved in a solvent, and thesolvent is not necessarily removed after forming the film. However, thevacuum evaporation method has disadvantages as follows. That is, inparticular, separate coating by using a metal mask is difficult. Inparticular, in forming a large panel, the vacuum evaporation methodleads to high facility manufacturing cost, is not applicable to a largescreen substrate, and is not suitable for mass production.

Thus, the wet method having an advantage that a large display screenarea is comparatively easily realized by the ink jet method and nozzlecoating method has attracted attentions.

SUMMARY

However, since a blue light emitting material does not show favorablelight emitting luminance and favorable life and is still not practical,patterning by coating method such as ink jet method and nozzle coatingmethod has been difficult.

Thus, in Japanese Patent No. 4062352 and Japanese Patent No. 3899566,the following manufacturing method is disclosed. In the manufacturingmethod, a red organic light emitting layer and a green organic lightemitting layer are formed by ink jet method, and a blue organic lightemitting layer is formed by evaporation. In the manufacturing method ofJapanese Patent No. 4062352 and Japanese Patent No. 3899566, the bluelight emitting layer is formed by evaporation method with the use of ahighly practical low molecular material. Thus, the cost is low, andthere is a high possibility to realize a large device. However, in viewof practicality, light emitting efficiency and life of a blue pixel arestill insufficient.

In view of the foregoing disadvantage, in the present application, it isdesirable to provide a method of manufacturing an organic EL displayunit and an organic EL display unit that are able to improve lightemitting efficiency and life of blue.

According to an embodiment, there is provided a method of manufacturingan organic EL display unit including steps of: forming a lower electroderespectively for a red organic EL device, a green organic EL device, anda blue organic EL device on a substrate; forming a hole injection layerrespectively for the red organic EL device, the green organic EL device,and the blue organic EL device on the lower electrode by coating method;forming a hole transport layer made of a polymer material respectivelyfor the red organic EL device and the green organic EL device on thehole injection layer by coating method; forming a red light emittinglayer made of a polymer material on the hole transport layer for the redorganic EL device by coating method; forming a green light emittinglayer made of a polymer material on the hole transport layer for thegreen organic EL device by coating method; forming a hole transportlayer made of a low molecular material on the hole injection layer ofthe blue organic EL device by coating method; forming a blue lightemitting layer made of a low molecular material on the whole area of thered light emitting layer, the green light emitting layer, and the holetransport layer for the blue organic EL device by evaporation method;and sequentially forming an electron transport layer, an electroninjection layer, and an upper electrode on the whole area of the bluelight emitting layer.

According to an embodiment, there is provided an organic EL display unitincluding: a lower electrode provided respectively for a red organic ELdevice, a green organic EL device, and a blue organic EL device on asubstrate; a hole injection layer provided respectively for the redorganic EL device, the green organic EL device, and the blue organic ELdevice on the lower electrode; a hole transport layer made of a polymermaterial provided respectively for the red organic EL device and thegreen organic EL device on the hole injection layer; a red lightemitting layer made of a polymer material provided on the hole transportlayer for the red organic EL device; a green light emitting layer madeof a polymer material provided on the hole transport layer for the greenorganic EL device; a hole transport layer made of a low molecularmaterial provided on the hole injection layer of the blue organic ELdevice; a blue light emitting layer made of a low molecular materialprovided on the whole area of the red light emitting layer, the greenlight emitting layer, and the hole transport layer for the blue organicEL device; and an electron transport layer, an electron injection layer,and an upper electrode sequentially provided on the whole area of theblue light emitting layer.

In the organic EL display unit of the embodiment, the hole transportlayer for the blue organic EL device is made of the low molecularmaterial. Thus, a state of interface with the blue light emitting layermade of the low molecular material is improved, and light emittingefficiency and life of blue are improved.

According to the method of manufacturing an organic EL display unit ofthe embodiment and the organic EL display unit of the embodiment, thehole transport layer made of the low molecular material is formed on thehole injection layer of the blue organic EL device by coating method.Thus, a state of interface with the blue light emitting layer made ofthe low molecular material is able to be improved, and light emittingefficiency and life of blue are able to be improved. Therefore, in thecolor organic EL display unit in which the red organic EL device, thegreen organic EL device, and the blue organic EL device are arranged,light emitting efficiency and life are further improved.

Additional features and advantages are described herein, and will beapparent from the following Detailed Description and the figures.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a diagram illustrating a structure of an organic EL displayunit according to an embodiment.

FIG. 2 is a diagram illustrating an example of a pixel drive circuitillustrated in FIG. 1.

FIG. 3 is a cross sectional view illustrating a structure of a displayregion illustrated in FIG. 1.

FIG. 4 is a chart illustrating a flow of a method of manufacturing theorganic EL display unit illustrated in FIG. 1.

FIGS. 5A to 5C are cross sectional views illustrating the manufacturingmethod illustrated in FIG. 4 in order of steps.

FIGS. 6A to 6C are cross sectional views illustrating steps followingFIGS. 5A to 5C.

FIGS. 7A to 7C are cross sectional views illustrating steps followingFIGS. 6A to 6C.

FIG. 8 is a plan view illustrating a schematic structure of a moduleincluding the display unit of the foregoing embodiment.

FIG. 9 is a perspective view illustrating an appearance of a firstapplication example of the display unit of the foregoing embodiment.

FIG. 10A is a perspective view illustrating an appearance viewed fromthe front side of a second application example, and FIG. 10B is aperspective view illustrating an appearance viewed from the rear side ofthe second application example.

FIG. 11 is a perspective view illustrating an appearance of a thirdapplication example.

FIG. 12 is a perspective view illustrating an appearance of a fourthapplication example.

FIG. 13A is an elevation view of a fifth application example unclosed,FIG. 13B is a side view thereof, FIG. 13C is an elevation view of thefifth application example closed, FIG. 13D is a left side view thereof,FIG. 13E is a right side view thereof, FIG. 13F is a top view thereof,and FIG. 13G is a bottom view thereof.

FIG. 14 is a diagram illustrating a result of an example.

FIG. 15 is a diagram illustrating a result of the example.

DETAILED DESCRIPTION

The present application which will be described in detail below withreference to the drawings according to an embodiment.

FIG. 1 illustrates a structure of an organic EL display unit accordingto an embodiment. The organic EL display unit is used as an organic ELtelevision device or the like. In the organic EL display unit, forexample, as a display region 110, a plurality of red organic EL devices10R, a plurality of green organic EL devices 10G, and a plurality ofblue organic EL devices 10B described later are arranged in a matrixstate over a substrate 11. A signal line drive circuit 120 and ascanning line drive circuit 130 that are drivers for displaying a videoare provided on the periphery of the display region 110.

In the display region 110, a pixel drive circuit 140 is provided. FIG. 2illustrates an example of the pixel drive circuit 140. The pixel drivecircuit 140 is an active drive circuit that is formed in a layer locatedlower than an after-mentioned lower electrode 14. In other words, thepixel drive circuit 140 has a drive transistor Tr1, a writing transistorTr2, a capacitor (retentive capacity) Cs between the transistors Tr1 andTr2, and the red organic EL device 10R (or the green organic EL device10G or the blue organic EL device 10B) serially connected to the drivetransistor Tr1 between a first power line (Vcc) and a second power line(GND). The drive transistor Tr1 and the writing transistor Tr2 arecomposed of a general thin film transistor (TFT). The structure thereofis not particularly limited, and may be, for example, inverselystaggered structure (so-called bottom gate type) or staggered structure(top gate type).

In the pixel drive circuit 140, a plurality of signal lines 120A arearranged in the column direction, and a plurality of scanning lines 130Aare arranged in the row direction. Each cross section between eachsignal line 120A and each scanning line 130A corresponds to one of thered organic EL device 10R, the green organic EL device 10G, and the blueorganic EL device 10B (sub pixel). Each signal line 120A is connected tothe signal line drive circuit 120. An image signal is supplied to asource electrode of the writing transistor Tr2 from the signal linedrive circuit 120 through the signal line 120A. Each scanning line 130Ais connected to the scanning line drive circuit 130. A scanning signalis sequentially supplied to a gate electrode of the writing transistorTr2 from the scanning line drive circuit 130 through the scanning line130A.

Further, in the display region 110, the red organic EL device 10Rgenerating red light, the green organic EL device 10G generating greenlight, and the blue organic EL device 10B generating blue light aresequentially arranged in a matrix state as a whole. A combination of thered organic EL device 10R, the green organic EL device 10G, and the blueorganic EL device 10B adjacent to each other composes one pixel.

FIG. 3 illustrates a cross sectional structure of the display region 110illustrated in FIG. 1. The red organic EL device 10R, the green organicEL device 10G, and the blue organic EL device 10B respectively have astructure in which a lower electrode 14 as an anode, a dividing wall 15,an organic layer 16 including a light emitting layer 16C describedlater, and an upper electrode 17 as a cathode are layered in this orderfrom the substrate 11 side with the drive transistor Tr1 of theforegoing pixel drive circuit 140 and a planarizing insulating film (notillustrated) in between.

The red organic EL device 10R, the green organic EL device 10G, and theblue organic EL device 10B as above are coated with a protective layer20. Further, a sealing substrate 40 made of glass or the like is bondedto the whole area of the protective layer 20 with an adhesive layer (notillustrated) such as a thermoset resin and an ultraviolet curable resinin between, and therefore the red organic EL device 10R, the greenorganic EL device 10G, and the blue organic EL device 10B are sealed.

The substrate 11 is a support body in which the red organic EL device10R, the green organic EL device 10G, and the blue organic EL device 10Bare arranged on one main face side. The substrate 11 may be a knownsubstrate, and is made of, for example, quartz, glass, a metal foil, aresin film, a resin sheet or the like. Specially, quartz and glass arepreferable. Examples of resin include a methacryl resin represented bypolymethyl methacrylate (PMMA), polyester such as polyethyleneterephthalate (PET), polyethylene naphthalate (PEN), and polybutylenenaphthalate (PBN), and a polycarbonate resin. A lamination structure anda surface treatment that inhibit water permeability and gas permeabilityshould be provided.

The lower electrode 14 is provided on the substrate 11 respective forthe red organic EL device 10R, the green organic EL device 10G, and theblue organic EL device 10B. The lower electrode 14 has a thickness inthe lamination direction (hereinafter simply referred to as thickness)of, for example, from 10 nm to 1000 nm both inclusive. Examples ofmaterial of the lower electrode 14 include a simple substance or analloy of metal elements such as chromium (Cr), gold (Au), platinum (Pt),nickel (Ni), copper (Cu), tungsten (W), and silver (Ag). Further, thelower electrode 14 may have a lamination structure of a metal film madeof a simple substance or an alloy of the foregoing metal elements and atransparent conductive film structured by, for example, an alloycomposed of an oxide of indium and tin (ITO)/InZnO (indium zincoxide)/zinc oxide (ZnO) and aluminum (Al). In the case where the lowerelectrode 14 is used as an anode, the lower electrode 14 is desirablymade of a material having high electron hole injection characteristics.If an appropriate electron hole injection layer is provided, it is ableto use a material that has a disadvantage of a hole injection barrierdue to existence of an oxide film on the surface and a small workfunction such as an aluminum (Al) alloy as the lower electrode 14.

The dividing wall 15 is intended to secure insulation between the lowerelectrode 14 and the upper electrode 17, and to obtain a desired shapeof the light emitting region. In addition, the dividing wall 15 alsofunctions as a dividing wall in coating by ink jet method or nozzlecoating method in the after-mentioned manufacturing step. The dividingwall 15 has an upper dividing wall 15B made of a photosensitive resinsuch as positive type photosensitive polybenzoxazole and positive typephotosensitive polyimide on a lower dividing wall 15A made of aninorganic insulating material such as SiO₂. The dividing wall 15 isprovided with an aperture corresponding to a light emitting region. Theorganic layer 16 and the upper electrode 17 may be provided not only inthe aperture but also on the dividing wall 15. However, it is only theaperture of the dividing wall 15 that emits light.

The organic layer 16 of the red organic EL device 10R has, for example,a structure in which a hole injection layer 16AR, a hole transport layer16BR, a red light emitting layer 16CR, a blue light emitting layer 16CB,an electron transport layer 16D, and an electron injection layer 16E arelayered sequentially from the lower electrode 14 side. The organic layer16 of the green organic EL device 10G has, for example, a structure inwhich a hole injection layer 16AG, a hole transport layer 16BG, a greenlight emitting layer 16CG, the blue light emitting layer 16CB, theelectron transport layer 16D, and the electron injection layer 16E arelayered sequentially from the lower electrode 14 side. The organic layer16 of the blue organic EL device 10B has, for example, a structure inwhich a hole injection layer 16AB, a hole transport layer 16BB, the bluelight emitting layer 16CB, the electron transport layer 16D, and theelectron injection layer 16E are layered sequentially from the lowerelectrode 14 side. Of the foregoing layers, the blue light emittinglayer 16CB, the electron transport layer 16D, and the electron injectionlayer 16E are provided as a common layer for the red organic EL device10R, the green organic EL device 10G, and the blue organic EL device10B.

The hole injection layers 16AR, 16AG, and 16AB are intended to improvethe hole injection efficiency and function as a buffer layer to preventleakage. The hole injection layers 16AR, 16AG, and 16AB are provided onthe lower electrode 14 respectively for the red organic EL device 10R,the green organic EL device 10G, and the blue organic EL device 10B.

The hole injection layers 16AR, 16AG, and 16AB preferably have, forexample, a thickness from 5 nm to 100 nm both inclusive, and morepreferably have a thickness from 8 nm to 50 nm both inclusive. Thecomponent material of the hole injection layers 16AR, 16AG, and 16AB maybe selected as appropriate according to relation with a material of anelectrode and a layer adjacent thereto. Examples thereof includepolyaniline and a derivative thereof, polythiophene and a derivativethereof, polypyrrole and a derivative thereof, polyphenylene vinyleneand a derivative thereof, polythienylene vinylene and a derivativethereof, polyquinoline and a derivative thereof, polyquinoxaline and aderivative thereof, a conductive polymer such as a polymer including anaromatic amine structure in a main chain or a side chain, metalphthalocyanine (copper phthalocyanine or the like), and carbon. In thecase where the material used for the hole injection layers 16AR, 16AG,and 16AB is a polymer material, the weight average molecular weight (Mw)of the polymer is preferably from 2000 to 10000 both inclusive as anoligomer or in the range from 10000 to 30000 both inclusive. Inparticular, the weight average molecular weight (Mw) of the polymer ispreferably from 5000 to 200000 both inclusive. If Mw is less than 5000,there is a possibility that the hole injection layer is dissolved informing layers on and after the hole transport layer. Further, if Mwexceeds 300000, there is a possibility that the material is gelated andfilm formation becomes difficult.

Examples of typical conductive polymers used as the component materialof the hole injection layers 16AR, 16AG, and 16AB include polyanilineand/or oligoaniline and polydioxythiophene such aspoly(3,4-ethylenedioxythiophene) (PEDOT). Examples thereof include apolymer commercially available under the name of Nafion (trademark) madeby H. C. starck, a polymer commercially available under the name ofLiquion (trademark) in a dissolved state, EL source (trademark) made byNissan Chemical Industries, Ltd., and Berazol (trademark) as aconductive polymer made by Soken Chemical&Engineering Co., Ltd.

The hole transport layers 16BR and 16BG of the red organic EL device 10Rand the green organic EL device 10G are intended to improve holetransport efficiency to the red light emitting layer 16CR and the greenlight emitting layer 16CG. The hole transport layers 16BR and 16BG areprovided on the hole injection layers 16AR and 16AG respectively for thered organic EL device 10R and the green organic EL device 10G.

The hole transport layers 16BR and 16BG preferably have, for example, athickness from 10 nm to 200 nm both inclusive, and more preferably havea thickness from 15 nm to 150 nm both inclusive though the thicknessdepends on the device whole structure. Examples of polymer materialscomposing the hole transport layers 16BR and 16BG include a lightemitting material dissolvable into an organic solvent such as polyvinylcarbazole and a derivative thereof, polyfluorene and a derivativethereof, polyaniline and a derivative thereof, polysilane and aderivative thereof, a polysiloxane derivative having an aromatic aminestructure in a main chain or a side chain, polythiophene and aderivative thereof, and polypyrrole.

The weight average molecular weight (Mw) of the polymer material ispreferably from 50000 to 300000 both inclusive, and in particular, ispreferably from 100000 to 200000 both inclusive. If Mw is less than50000, there is a possibility that in forming the light emitting layer,a low molecular component in the polymer material is dropped, and a dotis generated in the hole injection layer and the hole transport layer,and thus initial performance of the organic EL device may be lowered andthe device may be deteriorated. Meanwhile, if Mw exceeds 300000, thereis a possibility that the material is gelated and film formation becomesdifficult. The weight average molecular weight (Mw) is a value obtainedby finding the weight average molecular weight as a reduced quantity ofpolystyrene by gel permeation chromatography (GPC) with the use oftetrahydrofuran as a solvent.

The red light emitting layer 16CR and the green light emitting layer16CG are intended to generate light due to electron-hole recombinationby applying an electric field. The red light emitting layer 16CR and thegreen light emitting layer 16CG have, for example, a thickness from 10nm to 200 nm both inclusive, and preferably have a thickness from 15 nmto 150 nm both inclusive though the thickness depends on the devicewhole structure. Examples of polymer light emitting materials composingthe red light emitting layer 16CR and the green light emitting layer16CG include a polyfluorene polymer derivative, a(poly)paraphenylenevinylene derivative, a polyphenylene derivative, apolyvinyl carbazole derivative, a polythiophene derivative, perylenepigment, coumarin pigment, rhodamine pigment, and a material obtained bydoping an organic EL material into the foregoing polymer. For example, asubstance obtained by doping rubrene, perylene, 9,10 diphenylanthracene, tetraphenyl butadiene, nile red, and coumarin 6 is able tobe used

The hole transport layer 16BB of the blue organic EL device 10B isintended to improve hole transport efficiency to the blue light emittinglayer 16CB. The hole transport layer 16BB is provided on the holeinjection layer 16AB. The hole transport layer 16BB preferably has, forexample, a thickness from 10 nm to 200 nm both inclusive, and morepreferably has a thickness from 15 nm to 150 nm both inclusive thoughthe thickness depends on the device whole structure.

The hole transport layer 16BB contains a low molecular material.Therefore, in the organic EL display unit, light emitting efficiency andlife of blue are able to be improved. The low molecular material is acompound that is other than a substance composed of a high-molecularweight polymer or condensed body molecules generated by chain-likerepetition of the same or similar reaction of the low molecularcompound, and that has a single molecular weight substantively. Further,the low molecular material does not generate new chemical bond betweenmolecules substantively by heating, and exists as a mono-molecule.

Specific examples of materials of the hole transport layer 16BB includebenzine, styrilamine, triphenylamine, porphyrin, triphenylene,azatriphenylene, tetracyanoquinodimethane, triazole, imidazole,oxadiazole, polyarylalkane, phenylenediamine, arylamine, oxazole,anthracene, fluorenone, hydrazone, stilbene, a derivative thereof, and aheterocyclic conjugated monomer/oligomer/polymer such as a polysilanecompound, a vinyl carbazole compound, a thiophene compound, and ananiline compound.

Specific examples of materials of the hole transport layer 16BB includeα-naphtylphenylphenylenediamine, porphyrin, metal tetraphenyl porphyrin,metal naphthalocyanine, hexacyanoazatriphenylene,7,7,8,8-tetracyanoquinodimethane (TCNQ),7,7,8,8-tetracyano-2,3,5,6-tetrafluoroquinodimethane (F4-TCNQ),tetracyano 4,4,4-tris(3-methylphenylphenylamino)triphenylamine, N,N,N′-N′-tetrakis(p-tolyl)p-phenylene diamine,N,N,N′,N′-tetraphenyl-4,4′-diaminobiphenyl, N-phenylcarbazole,4-di-p-tolylaminostylbene, poly(paraphenylenevinylene),poly(thiophenevinylene), and poly(2,2′-thienylpyrrol). However, thematerial of the hole transport layer 16BB is not limited thereto.

A material structured by using an organic material expressed by thefollowing General formula 1 shown in following Chemical formula 1 ismore preferable.

In General formula 1, A1 to A3 respectively and independently representa substituted or unsubstituted aryl group or a substituted orunsubstituted heterocyclic group. Further, A1 to A3 may have anextension structure in which a plurality of rings is linked by conjugatebond respectively, but it is preferably that A1 to A3 have 30 or lesscarbon atoms in total. Further, examples of a substituted group bondedto the aryl group or the heterocyclic group include hydrogen, halogen, ahydroxyl group, a substituted or unsubstituted carbonyl group having 20or less carbon atoms, a substituted or unsubstituted carbonylester grouphaving 20 or less carbon atoms, a substituted or unsubstituted alkylgroup having 20 or less carbon atoms, a substituted or unsubstitutedalkenyl group having 20 or less carbon atoms, a substituted orunsubstituted alkoxyl group having 20 or less carbon atoms, a cyanogroup, a nitro group, and a substituted or unsubstituted amino grouphaving 30 or less carbon atoms.

Specific examples of such organic materials include Compounds 1(1) to1(60) shown in following Chemical formula 2 to Chemical formula 5.

The blue light emitting layer 16CB is intended to generate light due toelectron-hole recombination by being applied an electric field. The bluelight emitting layer 16CB is provided as a common layer on the wholearea of the red light emitting layer 16CR, the green light emittinglayer 16CG, and the hole transport layer 16BB for the blue organic ELdevice 10B. The blue light emitting layer 16CB is structured so that aguest material of blue or green fluorescent pigment is doped with theuse of an anthracene compound as a host material. The blue lightemitting layer 16CB emits blue or green light.

The host material composing the blue light emitting layer 16CB ispreferably an anthracene derivative expressed by General formula 2 shownin following Chemical formula 6.

In General formula 2, R1 to R6 respectively and independently representhydrogen, halogen, a hydroxyl group, a substituted or unsubstitutedcarbonyl group having 20 or less carbon atoms, a substituted orunsubstituted carbonylester group having 20 or less carbon atoms, asubstituted or unsubstituted alkyl group having 20 or less carbon atoms,a substituted or unsubstituted alkenyl group having 20 or less carbonatoms, a substituted or unsubstituted alkoxyl group having 20 or lesscarbon atoms, a cyano group, a nitro group, a substituted orunsubstituted silyl group having 30 or less carbon atoms, a substitutedor unsubstituted aryl group having 30 or less carbon atoms, asubstituted or unsubstituted heterocyclic group having 30 or less carbonatoms, or a substituted or unsubstituted amino group having 30 or lesscarbon atoms.

Examples of the aryl group represented by R1 to R6 in General formula 2include a phenyl group, a 1-naphtyl group, a 2-naphtyl group, afluorenyl group, a 1-anthryl group, a 2-anthryl group, a 9-anthrylgroup, a 1-phenanthryl group, a 2-phenanthryl group, a 3-phenanthrylgroup, a 4-phenanthryl group, a 9-phenanthryl group, a 1-naphthacenylgroup, a 2-naphthacenyl group, a 9-naphthacenyl group, a 1-pyrenylgroup, a 2-pyrenyl group, a 4-pyrenyl group, a 1-crycenyl group, a6-crycenyl group, a 2-fluoranethenyl group, a 3-fluoranethenyl group, a2-biphenylyl group, a 3-biphenylyl group, a 4-biphenylyl group, ano-tolyl group, an m-tolyl group, a p-tolyl group, and a p-t-butylphenylgroup.

Examples of the heterocyclic group represented by R1 to R6 in Generalformula 2 include a five-membered ring or a six-membered ring aromaticheterocyclic group containing O, N, and S as a hetero atom and acondensed polycyclic aromatic heterocyclic group having 2 to 20 carbonatoms. Further, examples of the aromatic heterocyclic group and thecondensed polycyclic aromatic heterocyclic group include a thienylgroup, a furyl group, a pyrrolyl group, a pyridyl group, a quinolylgroup, a quinoxalil group, an imidazopyridyl group, and a benzothiazolegroup. Representative examples thereof include a 1-pyrrolyl group, a2-pyrrolyl group, a 3-pyrrolyl group, a pyradinyl group, a 2-pyridinylgroup, a 3-pyridinyl group, a 4-pyridinyl group, a 1-indolyl group, a2-indolyl group, a 3-indolyl group, a 4-indolyl group, a 5-indolylgroup, a 6-indolyl group, a 7-indolyl group, a 1-isoindolyl group, a2-isoindolyl group, a 3-isoindolyl group, a 4-isoindolyl group, a5-isoindolyl group, a 6-isoindolyl group, a 7-isoindolyl group, a2-furyl group, a 3-furyl group, a 2-benzofuranyl group, a 3-benzofuranylgroup, a 4-benzofuranyl group, a 5-benzofuranyl group, a 6-benzofuranylgroup, a 7-benzofuranyl group, a 1-isobenzofuranyl group, a3-isobenzofuranyl group, a 4-isobenzofuranyl group, a 5-isobenzofuranylgroup, a 6-isobenzofuranyl group, a 7-isobenzofuranyl group, a quinolylgroup, a 3-quinolyl group, a 4-quinolyl group, a 5-quinolyl group, a6-quinolyl group, a 7-quinolyl group, an 8-quinolyl group, a1-isoquinolyl group, a 3-isoquinolyl group, a 4-isoquinolyl group, a5-isoquinolyl group, a 6-isoquinolyl group, a 7-isoquinolyl group, an8-isoquinolyl group, a 2-quinoxalinyl group, a 5-quinoxalinyl group, a6-quinoxalinyl group, a 1-carbazolyl group, a 2-carbazolyl group, a3-carbazolyl group, a 4-carbazolyl group, a 9-carbazolyl group, a1-phenanslidinyl group, a 2-phenanslidinyl group, a 3-phenanslidinylgroup, a 4-phenanslidinyl group, a 6-phenanslidinyl group, a7-phenanslidinyl group, an 8-phenanslidinyl group, a 9-phenanslidinylgroup, a 10-phenanslidinyl group, a 1-acrydinyl group, a 2-acrydinylgroup, a 3-acrydinyl group, a 4-acrydinyl group, and a 9-acrydinylgroup.

The amino group represented by R1 to R6 may be any of an alkylaminogroup, an arylamino group, and an aralkylamino group. Such groupspreferably have an aliphatic carbon ring having 1 to 6 carbon atoms intotal and/or a monocyclic to tetracyclic aromatic carbon ring. Examplesthereof include a dimethylamino group, a diethylamino group, adibutylamino group, a diphenylamino group, a ditrylamino group, abisbiphenyl amino group, and dinaphthylamino group.

Two or more of the foregoing substituted groups may form a condensedring, and may further have a substituted group.

Specific examples of the compound include compound 2(1) to 2(51) shownin following Chemical formula 7 to Chemical formula 9.

Meanwhile, as the light-emitting guest material composing the blue lightemitting layer 16CB, a material having high light emitting efficiencysuch as a low molecular fluorescent material and a phosphorescencepigment, or an organic light emitting material such as a metal complexis used.

The light emitting guest material of blue means a compound in which thelight emitting wavelength range shows the peak in the range about from400 nm to 490 nm. As such a compound, an organic material such as anaphthalene derivative, an anthracene derivative, a naphthacenederivative, a styrilamine derivative, and a bis(adinyl)methene boroncomplex is used. Specially, it is preferable to select a compound froman aminonaphthalene derivative, an aminoanthracene derivative, anaminochrysene derivative, an aminopyrene derivative, a styrylaminederivative, and a bis(adinyl)methene boron complex.

The electron transport layer 16D is intended to improve electrontransport efficiency to the red light emitting layer 16CR, the greenlight emitting layer 16CG, and the blue light emitting layer 16CB. Theelectron transport layer 16D is provided on the whole area of the bluelight emitting layer 16CB as a common layer. Examples of material of theelectron transport layer 16D include quinoline, perylene,phenanthroline, bisstyril, pyradine, triazole, oxazole, fullerene,oxadiazole, and fluorenone or a derivative and a metal complex thereof.Specific examples thereof include tris(8-hydroxyquinoline)aluminum(abbreviated to Alq₃), anthracene, naphthalene, phenanthrene, pyrene,anthracene, perylene, butadiene, coumarin, C60, acridine, stilbene,1,10-phenanthroline, and a derivative and a metal complex thereof.

The electron injection layer 16E is intended to improve electroninjection efficiency. The electron injection layer 16E is provided onthe whole area of the electron transport layer 16D as a common layer.Examples of material of the electron injection layer 16E include lithiumoxide (Li₂O) as an oxide of lithium (Li), cesium carbonate (Cs₂CO₃) as acomposite oxide of cesium (Cs), and a mixture of the oxide/the compositeoxide. Further, the material of the electron injection layer 16 is notlimited to the foregoing material. For example, an alkali earth metalsuch as calcium (Ca) and barium (Ba), an alkali metal such as lithiumand cesium, a metal having small work function such as indium (In) andmagnesium (Mg), an oxide/a composite oxide/a fluoride of these metals asa simple body or a mixture/an alloy of the metal/the oxide/the compositeoxide/the fluoride may be used by improving stability.

The upper electrode 17 has a thickness of, for example, from 3 nm to 8nm both inclusive, and is made of a metal conductive film. Specificexamples thereof include an alloy of aluminum (Al), magnesium (Mg),calcium (Ca), or sodium (Na). Specially, an alloy of magnesium andsilver (Mg—Ag alloy) is preferable, since the Mg—Ag alloy has electricconductivity and small absorption in a thin film. The ratio of magnesiumand silver in the Mg—Ag alloy is not particularly limited, but the filmthickness ratio of Mg:Ag is desirably in the range from 20:1 to 1:1.Further, the material of the upper electrode 17 may be an alloy ofaluminum (Al) and lithium (Li) (Al—Li alloy).

Further, the upper electrode 17 may be a mixed layer containing anorganic light emitting material such as an aluminum quinoline complex, astyrylamine derivative, and a phthalocyanine derivative. In this case,the upper electrode 17 may further separately have a layer having lighttransmittance such as MgAg as the third layer. In the case of activematrix drive system, the upper electrode 17 is formed as a film in asolid state over the substrate 11 in a state of being insulated from thelower electrode 14 by the organic layer 16 and the dividing wall 15, andis used as a common electrode for the red organic EL device 10R, thegreen organic EL device 10G, and the blue organic EL device 10B.

The protective layer 20 has a thickness of, for example, from 2 μm to 3μm both inclusive, and may be made of one of an insulating material anda conductive material. Preferable examples of the insulating materialinclude an inorganic amorphous insulating material such as amorphoussilicon (α-Si), amorphous silicon carbide (α-SiC), amorphous siliconnitride (α-Sil-xNx), and amorphous carbon (α-C). Such an inorganicamorphous insulating material does not structure grains, and thus thewater permeability is low and forms a favorable protective film.

The sealing substrate 40 is located on the upper electrode 17 side ofthe red organic EL device 10R, the green organic EL device 10G, and theblue organic EL device 10B. The sealing substrate 40 seals the redorganic EL device 10R, the green organic EL device 10G, and the blueorganic EL device 10B together with the adhesive layer (notillustrated). The sealing substrate 40 is made of a material such asglass transparent to light generated in the red organic EL device 10R,the green organic EL device 10G, and the blue organic EL device 10B. Thesealing substrate 40 is, for example, provided with a color filter and alight shielding film as a black matrix (both not illustrated), whichextracts the light generated in the red organic EL device 10R, the greenorganic EL device 10G, and the blue organic EL device 10B, and absorbsoutside light reflected by the red organic EL device 10R, the greenorganic EL device 10G, and the blue organic EL device 10B and the wiringin between to improve contrast.

The color filter has a red filter, a green filter, and a blue filter(all not illustrated), which are sequentially arranged correspondinglyto the red organic EL device 10R, the green organic EL device 10G, andthe blue organic EL device 10B. The red filter, the green filter, andthe blue filter are respectively formed in the shape of, for example, arectangle with no space in between. The red filter, the green filter,and the blue filter are respectively made of a resin mixed with apigment. Adjustment is made by selecting a pigment so that lighttransmittance in the intended red, green, or blue wavelength region ishigh, and light transmittance in the other wavelength regions is low.

Further, the wavelength range with high transmittance in the colorfilter corresponds with a peak wavelength λ of spectrum of light that isdesired to be extracted from a resonator structure MC1. Therefore, outof outside light entering from the sealing substrate 40, only outsidelight having a wavelength equal to the peak wavelength λ of the spectrumof the light that is desired to be extracted is transmitted through thecolor filter. Outside light having the other wavelength is preventedfrom intruding into the organic EL devices 10R, 10G, and 10B.

The light shielding film is composed of a black resin film having anoptical density of 1 or more in which a black colorant is mixed or athin film filter by using thin film interference. Of the foregoing, thelight shielding film is preferably composed of the black resin film,since thereby the film is able to be formed inexpensively and easily.The thin film filter is obtained by layering one or more thin filmscomposed of a metal, a metal nitride, or a metal oxide, and is intendedto attenuate light by using thin film interference. Specific examples ofthe thin film filter include a filter in which chromium and chromiumoxide (III)(Cr₂O₃) are alternately layered.

The organic EL display unit is able to be manufactured, for example, asfollows.

FIG. 4 illustrates a flow of a method of manufacturing the organic ELdisplay unit. FIG. 5A to FIG. 7C illustrate the method of manufacturingthe organic EL display unit illustrated in FIG. 4 in order of steps.First, the pixel drive circuit 140 including the drive transistor Tr1 isformed on the substrate 11 made of the foregoing material, and theplanarizing insulating film (not illustrated) made of, for example, aphotosensitive resin is provided.

Step of Forming the Lower Electrode 14

Next, a transparent conductive film made of, for example, ITO is formedon the whole area of the substrate 11. The transparent conductive filmis patterned and therefore, as illustrated in FIG. 5A, the lowerelectrode 14 is formed respectively for the red organic EL device 10R,the green organic EL device 10G, and the blue organic EL device 10B(step S101). At this time, the lower electrode 14 is conducted to thedrain electrode of the drive transistor Tr1 through a contact hole (notillustrated) of the planarizing insulating film (not illustrated).

Step of Forming the Dividing Wall 15

Subsequently, as illustrated in FIG. 5A again, an inorganic insulatingmaterial such as SiO₂ is deposited on the lower electrode 14 and theplanarizing insulating film (not illustrated) by, for example, CVD(Chemical Vapor Deposition) method. The resultant is patterned by usingphotolithography technology and etching technology, and therefore thelower dividing wall 15A is formed.

Thereafter, as illustrated in FIG. 5A again, the upper dividing wall 15Bmade of the foregoing photosensitive resin is formed in a given positionof the lower dividing wall 15A, more specifically in a positionsurrounding the light emitting region of a pixel. Therefore, thedividing wall 15 composed of the lower dividing wall 15A and the upperdividing wall 15B is formed (step S102).

After the dividing wall 15 is formed, surface on the side where thelower electrode 14 and the dividing wall 15 are formed on the substrate11 is treated with oxygen plasma. Contamination such as an organicmaterial adhered to the surface is removed to improve wettingcharacteristics. Specifically, the substrate 11 is heated up to, forexample, about 70 degrees centigrade to 80 degrees centigrade, and issubsequently treated with plasma (O₂ plasma treatment) with the use ofoxygen as reaction gas under atmospheric pressure.

Step of Providing Water Repellent Treatment

After the plasma treatment is provided, water repellent treatment(liquid repellent treatment) is provided (step S103). Therefore, inparticular, wetting characteristics on the top face and the side face ofthe upper dividing wall 15B are lowered. Specifically, plasma treatment(CF₄ plasma treatment) with the use of methane tetrafluoride as reactiongas is provided under atmospheric pressure. Thereafter, the substrate 11heated for the plasma treatment is cooled down to room temperature.Therefore, the top face and the side face of the upper dividing wall 15Bare treated to have liquid repellent characteristics, and therefore thewetting characteristics thereof are lowered.

In the CF₄ plasma treatment, an exposed face of the lower electrode 14and the lower dividing wall 15A are somewhat affected. However, ITO as amaterial of the lower electrode 14 and SiO₂ or the like as a componentmaterial of the lower dividing wall 15A have a low affinity to fluorine.Thus, in the face with the wetting characteristics improved by theoxygen plasma treatment, the wetting characteristics are retained.

Step of Forming the Hole Injection Layers 16AR, 16AG, and 16AB

After the water repellent treatment is provided, as illustrated in FIG.5B, the hole injection layers 16AR, 16AG, and 16AB made of the foregoingmaterial are formed in the region surrounded by the upper dividing wall15B (step S104). The hole injection layers 16AR, 16AG, and 16AB areformed by coating method such as spin coating method and dropletdischarge method. In particular, since the formation material of thehole injection layers 16AR, 16AG, and 16AB should be selectivelyarranged in the region surrounded by the upper dividing wall 15B, inkjet method or nozzle coating method as a droplet discharge method ispreferably used.

Specifically, for example, by ink jet method, a solution or dispersionliquid of polyaniline, polythiophene or the like as the formationmaterial of the hole injection layers 16AR, 16AG, and 16AB is arrangedon the exposed face of the lower electrode 14. Thereafter, by providingheat treatment (dry treatment), the hole injection layers 16AR, 16AG,and 16AB are formed.

In the heat treatment, a solvent or a dispersion medium is dried andheated at high temperature. In the case where a conductive polymer suchas polyaniline and polythiophene is used, air atmosphere or oxygenatmosphere is preferable, since the conductive polymer is oxidized byoxygen and therefore conductivity is easily expressed.

Heating temperature is preferably from 150 degrees centigrade to 300degrees centigrade both inclusive, and more preferably from 180 degreescentigrade to 250 degrees centigrade both inclusive. Heating time ispreferably about from 5 minutes to 300 minutes, and more preferably from10 minutes to 240 minutes both inclusive though time depends ontemperature and atmosphere. The film thickness after drying ispreferably from 5 nm to 100 nm both inclusive, and more preferably from8 nm to 50 nm both inclusive.

Step of Forming the Hole Transport Layers 16BR and 16BG of the RedOrganic EL Device 10R and the Green Organic EL Device 10G

After the hole injection layers 16AR, 16AG, and 16AB are formed, asillustrated in FIG. 5C, the hole transport layers 16BR and 16BG made ofthe foregoing polymer material are formed on the hole injection layers16AR and 16AG respectively for the red organic EL device 10R and thegreen organic EL device 10G (step S105). The hole transport layers 16BRand 16BG are formed by coating method such as spin coating method anddroplet discharge method. In particular, since the formation material ofthe hole transport layers 16BR and 16BG should be selectively arrangedin the region surrounded by the upper dividing wall 15B, ink jet methodor nozzle coating method as a droplet discharge method is preferablyused.

Specifically, for example, by ink jet method, a solution or dispersionliquid of a polymer as the formation material of the hole transportlayers 16BR and 16BG is arranged on the exposed face of the holeinjection layers 16AR and 16AG. Thereafter, by providing heat treatment(dry treatment), the hole transport layers 16BR and 16BG of the redorganic EL device 10R and the green organic EL device 10G are formed.

In the heat treatment, a solvent or a dispersion medium is dried andheated at high temperature. As atmosphere in which coating is performedand the solvent is dried and heated, atmosphere having a main componentof nitrogen (N2) is preferable. If oxygen and moisture exists, there isa possibility that light emitting efficiency and life of the formedorganic EL display unit are lowered. In particular, in the heating step,influence of oxygen and moisture is large, to which attention should bepaid. The oxygen concentration is preferably from 0.1 ppm to 100 ppmboth inclusive, and more preferably 50 ppm or less. In the case whereoxygen with a concentration larger than 100 ppm exists, the interface ofthe formed thin film is contaminated, and therefore there is apossibility that light emitting efficiency and life of the obtainedorganic EL display unit are lowered. Further, in the case where oxygenwith a concentration smaller than 0.1 ppm exists, though devicecharacteristics are not damaged, cost of equipment for keeping theconcentration of atmosphere smaller than 0.1 ppm may be extremely largein the current mass production process. Further, regarding moisture, forexample, the dew point is preferably from −80 degrees centigrade to −40degrees centigrade both inclusive, more preferably −50 degreescentigrade or less, and much more preferably −60 degrees centigrade orless. In the case where moisture having a dew point higher than −40degrees centigrade exists, there is a possibility that the interface ofthe formed thin film is contaminated, and light emitting efficiency andlife of the obtained organic EL display unit are lowered. Further, inthe case where moisture having a dew point lower than −80 degreescentigrade exists, though device characteristics are not damaged, costof equipment for keeping the dew point lower than −80 degrees centigrademay be extremely large in the current mass production process.

Heating temperature is preferably from 100 degrees centigrade to 230degrees centigrade both inclusive, and more preferably from 100 degreescentigrade to 200 degrees centigrade both inclusive. Heating temperatureis preferably at least lower than the temperature at which the holeinjection layers 16AR, 16AG, and 16AB are formed. Time is preferablyabout from 5 minutes to 300 minutes both inclusive, and more preferablyfrom 10 minutes to 240 minutes both inclusive though time depends ontemperature and atmosphere. The film thickness after drying ispreferably from 10 nm to 200 nm both inclusive, and more preferably from15 nm to 150 nm both inclusive though the film thickness depends on thewhole structure of the device.

Step of forming the red light emitting layer 16CR and the green lightemitting layer 16CG

After the hole transport layers 16BR and 16BG of the red organic ELdevice 10R and the green organic EL device 10G are formed, asillustrated in FIG. 6A, the red light emitting layer 16CR made of theforegoing polymer material is formed on the hole transport layer 16BR ofthe red organic EL device. Further, the green light emitting layer 16CGmade of the foregoing polymer material is formed on the hole transportlayer 16BG of the green organic EL device (step S106). The red lightemitting layer 16CR and the green light emitting layer 16CG are formedby coating method such as spin coating method and droplet dischargemethod. In particular, since the formation material of the red lightemitting layer 16CR and the green light emitting layer 16CG should beselectively arranged in the region surrounded by the upper dividing wall15B, ink jet method or nozzle coating method as a droplet dischargemethod is preferably used.

Specifically, for example, by ink jet method, a solution or dispersionliquid of a polymer as the formation material of the red light emittinglayer 16CR and the green light emitting layer 16CG is arranged on theexposed face of the hole transport layers 16BR and 16BG. Thereafter, byproviding heat treatment (dry treatment), the red light emitting layer16CR and the green light emitting layer 16CG are formed.

In the heat treatment, a solvent or a dispersion medium is dried andheated at high temperature. As atmosphere in which coating is performedand the solvent is dried and heated, atmosphere having a main componentof nitrogen (N2) is preferable. If oxygen and moisture exists, there isa possibility that light emitting efficiency and life of the formedorganic EL display unit are lowered. In particular, in the heating step,influence of oxygen and moisture is large, to which attention should bepaid. The oxygen concentration is preferably from 0.1 ppm to 100 ppmboth inclusive, and more preferably 50 ppm or less. In the case whereoxygen with a concentration larger than 100 ppm exists, there is apossibility that the interface of the formed thin film is contaminated,and therefore light emitting efficiency and life of the obtained organicEL display unit are lowered. Further, in the case where oxygen with aconcentration smaller than 0.1 ppm exists, though device characteristicsare not damaged, cost of equipment for keeping the concentration ofatmosphere smaller than 0.1 ppm may be extremely large in the currentmass production process. Further, regarding moisture, for example, thedew point is preferably from −80 degrees centigrade to −40 degreescentigrade both inclusive, more preferably −50 degrees centigrade orless, and much more preferably −60 degrees centigrade or less. In thecase where moisture having a dew point larger than −40 degreescentigrade exists, the interface of the formed thin film iscontaminated, and therefore there is a possibility that light emittingefficiency and life of the obtained organic EL display unit are lowered.Further, in the case where moisture having a dew point lower than −80degrees centigrade exists, though device characteristics are notdamaged, cost of equipment for keeping the dew point lower than −80degrees centigrade may be extremely large in the current mass productionprocess.

Heating temperature is preferably from 100 degrees centigrade to 230degrees centigrade both inclusive, and more preferably from 100 degreescentigrade to 200 degrees centigrade both inclusive. Heating temperatureis preferably at least lower than the temperature at which the holeinjection layers 16AR, 16AG, and 16AB are formed. Time is preferablyabout from 5 minutes to 300 minutes both inclusive, and more preferablyfrom 10 minutes to 240 minutes both inclusive though time depends ontemperature and atmosphere. The film thickness after drying ispreferably from 10 nm to 200 nm both inclusive, and more preferably from15 nm to 150 nm both inclusive though the film thickness depends on thewhole structure of the device.

Step of Forming the Hole Transport Layer 16BB of the Blue Organic ELDevice 10B

After the red light emitting layer 16CR and the green light emittinglayer 16CG are formed, as illustrated in FIG. 6B, the hole transportlayer 16BB made of the foregoing low molecular material is formed on thehole injection layer 16AB for the blue organic light emitting device 10B(step S107). The hole transport layer 16BB is formed by coating methodsuch as spin coating method and droplet discharge method. In particular,since the formation material of the hole transport layer 16BB should beselectively arranged in the region surrounded by the upper dividing wall15B, ink jet method or nozzle coating method as a droplet dischargemethod is preferably used.

Specifically, for example, by ink jet method, a low molecular solutionor low molecular dispersion liquid as the formation material of the holetransport layer 16BB is arranged on the exposed face of the holeinjection layer 16AB. Thereafter, by providing heat treatment (drytreatment), the hole transport layer 16BB is formed.

In the heat treatment, a solvent or a dispersion medium is dried andheated at high temperature. As atmosphere in which coating is performedand the solvent is dried and heated, atmosphere having a main componentof nitrogen (N2) is preferable. If oxygen and moisture exists, there isa possibility that light emitting efficiency and life of the formedorganic EL display unit are lowered. In particular, in the heating step,influence of oxygen and moisture is large, to which attention should bepaid. The oxygen concentration is preferably from 0.1 ppm to 100 ppmboth inclusive, and more preferably 50 ppm or less. In the case whereoxygen with a concentration larger than 100 ppm exists, there is apossibility that the interface of the formed thin film is contaminated,and therefore light emitting efficiency and life of the obtained organicEL display unit are lowered. Further, in the case where oxygen with aconcentration smaller than 0.1 ppm exists, though device characteristicsare not damaged, cost of equipment for keeping the concentration ofatmosphere smaller than 0.1 ppm may be extremely large in the currentmass production process. Further, regarding moisture, for example, thedew point is preferably from −80 degrees centigrade to −40 degreescentigrade both inclusive, more preferably −50 degrees centigrade orless, and much more preferably −60 degrees centigrade or less. In thecase where moisture having a dew point higher than −40 degreescentigrade exists, the interface of the formed thin film iscontaminated, and therefore there is a possibility that light emittingefficiency and life of the obtained organic EL display unit are lowered.Further, in the case where moisture having a dew point lower than −80degrees centigrade exists, though device characteristics are notdamaged, cost of equipment for keeping the dew point lower than −80degrees centigrade may be extremely large in the current mass productionprocess.

Heating temperature is preferably from 100 degrees centigrade to 230degrees centigrade both inclusive, and more preferably from 100 degreescentigrade to 200 degrees centigrade both inclusive though heatingtemperature depends on characteristics of the material. Heatingtemperature is preferably at least lower than the temperature at whichthe hole injection layers 16AR, 16AG, and 16AB are formed. Further, ifheating is continued at temperature excessively exceeding Tg of the lowmolecular material, characteristics may be largely lowered. Heating timeis preferably about from 5 minutes to 300 minutes both inclusive, andmore preferably from 10 minutes to 240 minutes both inclusive thoughtime depends on temperature and atmosphere. The film thickness afterdrying is preferably from 10 nm to 200 nm both inclusive, and morepreferably from 15 nm to 150 nm both inclusive though the film thicknessdepends on the whole structure of the device.

Order of Steps

The step of forming the hole transport layers 16BR and 16BG of the redorganic EL device 10R and the green organic EL device 10G, the step offorming the hole transport layer 16BB of the blue organic EL device 10B,and the step of forming the red light emitting layer 16CR and the greenlight emitting layer 16CG may be performed in any order. However, it isnecessary that at least a base on which a layer to be formed isdeveloped is previously formed, and the heating step of the respectiveheating and drying steps is performed between each step. Further, it isnecessary that coating is provided so that temperature in the heatingstep is equal to or lower than temperature in the previous step. Forexample, in the case where heating temperature of the red light emittinglayer 16CR and the green light emitting layer 16CG is 130 degreescentigrade and heating temperature of the hole transport layer 16BB forthe blue organic EL device 10B is 130 degrees centigrade as well, it maybe possible that coating of the red light emitting layer 16CR and thegreen light emitting layer 16CG is performed without drying andcontinuously coating of the hole transport layer 16BB for the blueorganic EL device 10B is performed, and subsequently the drying andheating step of the red light emitting layer 16CR, the green lightemitting layer 16CG, and the hole transport layer 16BB for the blueorganic EL device 10B is performed. Further, in the foregoing respectivesteps, drying and heating are preferably performed as a separate stepfor the following reason. In the drying step, a coated wet film issignificantly easily flown, and thus film unevenness is easilygenerated. A preferable drying step is a method of uniformly dryingunder vacuum and at normal pressures. Further, drying without wind blowis desirable. In the heating step, the solvent is evaporated to someextent and the fluidity is lowered, the film is hardened. By slowlyapplying heat to the hardened film, a slight amount of remaining solventis able to be removed, and the light emitting material and the materialof the hole transport layer are able to be provided with rearrangementat molecular level.

Step of Forming the Blue Light Emitting Layer 16CB

After the hole transport layer 16BB for the blue organic EL device 10B,the red light emitting layer 16CR, and the green light emitting layer16CG are formed, as illustrated in FIG. 6C, the blue light emittinglayer 16CB made of the foregoing low molecular material is formed as acommon layer on the whole area of the red light emitting layer 16CR, thegreen light emitting layer 16CG, and the hole transport layer 16BB forthe blue organic EL device 10B (step S108).

Step of Forming the Electron Transport Layer 16D, the Electron InjectionLayer 16E, and the Upper Electrode 17

After the blue light emitting layer 16CB is formed, as illustrated inFIG. 7A, FIG. 7B, and FIG. 7C, the electron transport layer 16D, theelectron injection layer 16E, and the upper electrode 17 made of theforegoing material are formed on the whole area of the blue lightemitting layer 16CB by evaporation method (steps S109, S110, and S111).

After the upper electrode 17 is formed, as illustrated in FIG. 3, theprotective layer 20 is formed by film forming method such as evaporationmethod and CVD method in which film formation particle energy is smallto the degree at which little effect exists on the base. For example, inthe case where the protective layer 20 composed of amorphous siliconnitride is formed, a film having a film thickness from 2 to 3 μm bothinclusive is formed by CVD method. At this time, film formingtemperature is desirably set to normal temperature to prevent luminancelowering due to deterioration of the organic layer 16, and film formingis desirably performed under conditions that the film stress is theminimum to prevent exfoliation of the protective layer 20.

The blue light emitting layer 16CB, the electron transport layer 16D,the electron injection layer 16E, the upper electrode 17, and theprotective layer 20 are fully formed in a state of a solid film withoutusing a mask. Further, forming of the blue light emitting layer 16CB,the electron transport layer 16D, the electron injection layer 16E, theupper electrode 17, and the protective layer 20 is desirably performedcontinuously in the same film forming equipment without being exposed inthe air. Therefore, deterioration of the organic layer 16 due tomoisture in the air is prevented.

In the case where an auxiliary electrode (not illustrated) is formed inthe same step as that of the lower electrode 14, the organic layer 16formed in a state of a solid film on the auxiliary electrode may beremoved by a method such as laser ablation before forming the upperelectrode 17. Therefore, the upper electrode 17 is able to be directlyconnected to the auxiliary electrode, and contact is improved.

After the protective film 20 is formed, for example, the light shieldingfilm made of the foregoing material is formed on the sealing substrate40 made of the foregoing material. Subsequently, the sealing substrate40 is coated with a material of the red filter (not illustrated) by spincoating method or the like. The resultant is patterned byphotolithography technology, burned, and therefore the red filter isformed. Subsequently, the blue filter (not illustrated) and the greenfilter (not illustrated) are sequentially formed in the same manner asin the red filter (not illustrated).

Thereafter, the adhesive layer (not illustrated) is formed on theprotective layer 20, and the sealing substrate 40 and the protectivelayer 20 are bonded with the adhesive layer in between. Accordingly, thedisplay unit illustrated in FIG. 1 to FIG. 3 is completed.

In the display unit, the scanning signal is supplied to each pixelthrough the gate electrode of the writing transistor Tr2 from thescanning line drive circuit 130, and the image signal from the signalline drive circuit 120 is retained in the retentive capacity Cs throughthe writing transistor Tr2. In other words, the drive transistor Tr1 ison/off controlled according to the signal retained in the retentivecapacity Cs, and therefore drive current Id is injected into the redorganic EL device 10R, the green organic EL device 10G, and the blueorganic EL device 10B, electron-hole recombination is generated, andtherefore light is emitted. The light is transmitted through the lowerelectrode 14 and the substrate 11 in the case of bottom emission, and istransmitted through the upper electrode 17, the color filter (notillustrated), and the sealing substrate 40 in the case of top emission,and is extracted.

At this time, in the red organic EL device 10R, the red light emittinglayer 16CR and the blue light emitting layer 16CB are provided, energytransfer is generated in red having the lowest energy level, and redlight emission is dominant. In the green organic EL device 10G, thegreen light emitting layer 16CG and the blue light emitting layer 16CBare provided, energy transfer is generated in green having lower energylevel, and green light emission is dominant. In the blue organic ELdevice 10B, since only the blue light emitting layer 16CB is provided,blue light emission is generated. In this case, the hole transport layer16BB for the blue organic EL device 10B is made of the low molecularmaterial. Thus, state of the interface with the blue light emittinglayer 16CB made of the low molecular material is improved, and lightemitting efficiency and life of blue are improved.

As described above, in this embodiment, the hole transport layer 16BBmade of the low molecular material is formed on the hole injection layer16AB of the blue organic EL device 10B by coating method. Thus, state ofthe interface with the blue light emitting layer 16CB made of the lowmolecular material is able to be improved, and light emitting efficiencyand life of blue are able to be improved. Thus, in the color organic ELdisplay unit in which the red organic EL device 10R, the green organicEL device 10G, and the blue organic EL device 10B are arranged, lightemitting efficiency and life are further improved. In addition,difficulty of patterning in evaporation is able to be resolved, and lowcost is able to be realized by printing process.

Module and Application Examples

A description will be given of application examples of the organic ELdisplay unit described in the foregoing embodiment. The organic ELdisplay unit of the foregoing embodiment is able to be applied to adisplay unit of an electronic device in any field for displaying a videosignal inputted from outside or a video signal generated inside as animage or a video, such as a television device, a digital camera, anotebook personal computer, a portable terminal device such as a mobilephone, and a video camera.

Module

The organic EL display unit of the foregoing embodiment is incorporatedin various electronic devices such as after-mentioned first to fifthapplication examples as a module as illustrated in FIG. 8, for example.In the module, for example, a region 210 exposed from the protectivelayer 20 and the sealing substrate 40 is provided on one side of thesubstrate 11, and an external connection terminal (not illustrated) isformed in the exposed region 210 by extending the wirings of the signalline drive circuit 120 and the scanning line drive circuit 130. Theexternal connection terminal may be provided with a Flexible PrintedCircuit (FPC) 220 for inputting and outputting a signal.

First Application Example

FIG. 9 is an appearance of a television device to which the organic ELdisplay unit of the foregoing embodiment is applied. The televisiondevice has, for example, a video display screen section 300 including afront panel 310 and a filter glass 320. The video display screen section300 is composed of the organic EL display unit according to theforegoing embodiment.

Second Application Example

FIGS. 10A and 10B are an appearance of a digital camera to which theorganic EL display unit of the foregoing embodiment is applied. Thedigital camera has, for example, a light emitting section for a flash410, a display section 420, a menu switch 430, and a shutter button 440.The display section 420 is composed of the organic EL display unitaccording to the foregoing embodiment.

Third Application Example

FIG. 11 is an appearance of a notebook personal computer to which theorganic EL display unit of the foregoing embodiment is applied. Thenotebook personal computer has, for example, a main body 510, a keyboard520 for operation of inputting characters and the like, and a displaysection 530 for displaying an image. The display section 530 is composedof the organic EL display unit according to the foregoing embodiment.

Fourth Application Example

FIG. 12 is an appearance of a video camera to which the organic ELdisplay unit of the foregoing embodiment is applied. The video camerahas, for example, a main body 610, a lens 620 for shooting an objectprovided on the front side face of the main body 610, a start/stopswitch in shooting 630, and a display section 640. The display section640 is composed of the organic EL display unit according to theforegoing embodiment.

Fifth Application Example

FIGS. 13A to 13G are an appearance of a mobile phone to which theorganic EL display unit of the foregoing embodiment is applied. In themobile phone, for example, an upper package 710 and a lower package 720are jointed by a joint section (hinge section) 730. The mobile phone hasa display 740, a sub-display 750, a picture light 760, and a camera 770.The display 740 or the sub-display 750 is composed of the organic ELdisplay unit according to the foregoing embodiment.

EXAMPLES

A description will be given of specific examples of the application.

Example 1

The substrate 11 having dimensions of 25 mm×25 mm was formedrespectively for the red organic EL device 10R, the green organic ELdevice 10G, and the blue organic EL device 10B.

First, as the substrate 11, a glass substrate (25 mm×25 mm) wasprepared. On the substrate 11, as the lower electrode 14, a two-layerstructure composed of a silver alloy layer made of an Ag—Pd—Cu alloyhaving a thickness of 120 nm and a transparent conductive film made ofITO having a thickness of 10 nm was formed (step 101).

Subsequently, as the hole injection layers 16AR, 16AG, and 16AB, ND1501(polyaniline, made by Nissan Chemical Industries Ltd.) was coated toobtain a thickness of 15 nm by spin coating method in the air, and theresultant was thermally hardened on a hot plate for 30 minutes at 220degrees centigrade (step S104).

Thereafter, the hole injection layers 16AR and 16AG were coated with apolymer expressed by Structural formula 3(1) shown in Chemical formula10 as the hole transport layers 16BR and 16BG by spin coating method inN2 (dew point: −60 degrees centigrade, oxygen concentration: 10 ppm).The thickness of the hole transport layer 16BR for the red organic ELdevice 10R was 100 nm, and the thickness of the hole transport layer16BG of the green organic EL device 10G was 90 nm. Thereafter, theresultant was thermally hardened on a hot plate for 60 minutes at 180degrees centigrade in N2 (dew point: −60 degrees centigrade, oxygenconcentration: 10 ppm) (step S105).

After the hole transport layers 16BR and 16BG were formed, the holetransport layer 16BR of the red organic EL device 10R was coated with afluorenone polyarylene material having benzothiadiazole as a block asthe red light emitting layer 16CR by spin coating method to have athickness of 80 nm. Further, the hole transport layer 16BG of the greenorganic EL device 10G was coated with a fluorenone polyarylene materialhaving anthracene as a block as the green light emitting layer 16CG byspin coating method to have a thickness of 60 nm. Subsequently, theresultant was thermally hardened on a hot plate for 10 minutes at 130degrees centigrade in N2 (dew point: −60 degrees centigrade, oxygenconcentration: 10 ppm) (step S106).

After the red light emitting layer 16CR and the green light emittinglayer 16CG were formed, the hole injection layer 16AB for the blueorganic EL device 10B was coated with a low molecular material expressedby Structural formula 1(56) shown in Chemical formula 11 as the holetransport layer 16BB by spin coating method to obtain a thickness of 50nm. Thereafter, the resultant was heated on a hot plate for 60 minutesat 100 degrees centigrade in N2 (dew point: −60 degrees centigrade,oxygen concentration: 10 ppm) (step S107).

After the hole transport layer 16BB was formed, the substrate 11 for thered organic EL device 10R in which layers up to the red light emittinglayer 16CR were formed, the substrate 11 for the green organic EL device10G in which layers up to the green light emitting layer 16CG wereformed, and the substrate 11 for the blue organic EL device 10B in whichlayers up to the hole transport layer 16BB were formed were moved into avacuum evaporator, and layers on and after the blue light emitting layer16CB were evaporated.

First, as the blue light emitting layer 16CB, ADN (9,10-di(2-naphthyl)anthracene) (Structural formula 2(20)) shown in Chemical formula 12 anda blue dopant (Structural formula 103) shown in Chemical formula 13 wereco-evaporated at a ratio of 95:5 (step S108).

After the blue light emitting layer 16CB was formed, Alq3(8-hydroxyquinoline aluminum) (Structural formula 104) shown in Chemicalformula 14 as the electron transport layer 16D was evaporated by vacuumevaporation method (step S109). Subsequently, by evaporation methodagain, LiF as the electron injection layer 16E was formed to obtain athickness of 0.3 nm (step S110), and Mg—Ag as the upper electrode 17 wasformed to obtain a thickness of 10 nm (step S111). Finally, theprotective layer 20 composed of SiN was formed by CVD method, and solidsealing was provided by using a transparent resin. The red organic ELdevice 10R, the green organic EL device 10G, and the blue organic ELdevice 10B obtained as above were combined, and therefore a full colororganic EL display unit was obtained.

Comparative Example 1

An organic EL display unit was fabricated in the same manner as that ofExample 1, except that the polymer material (Structural formula 3(1))shown in Chemical formula 10 was used in the step of forming the holetransport layer of the blue organic EL device in the procedure offabricating the organic EL display unit described in Example 1.

Comparative Example 2

An organic EL display unit was fabricated in the same manner as that ofExample 1, except that a polymer material (Structural formula 3(2))shown in Chemical formula 15 was used in the step of forming the holetransport layer of the red organic EL device and the green organic ELdevice and the hole transport layer of the blue organic EL devicedescribed in Example 1.

Example 2

An organic EL display unit was fabricated in the same manner as that ofExample 1, except that Structural formula 1(58) shown in Chemicalformula 16 was used in the step of forming the hole transport layer 16BBof the blue organic EL device 10B described in Example 1.

Example 3

An organic EL display unit was fabricated in the same manner as that ofExample 1, except that Structural formula 1(22) shown in Chemicalformula 17 was used in the step of forming the hole transport layer 16BBof the blue organic EL device 10B described in Example 1.

Example 4

An organic EL display unit was fabricated in the same manner as that ofExample 1, except that Structural formula 1(23) shown in Chemicalformula 18 was used in the step of forming the hole transport layer 16BBof the blue organic EL device 10B described in Example 1.

Examples 5 to 9 Influence of Heating Temperature

An organic EL display unit was fabricated in the same manner as that ofExample 1, except that the heating temperature after forming the holetransport layer 16BB of the blue organic EL device 10B described inExample 1 was changed to 50 degrees centigrade in Example 5, 80 degreescentigrade in Example 6, 130 degrees centigrade in Example 7, 150degrees centigrade in Example 8, and 180 degrees centigrade in Example9.

Examples 10 to 14 Influence of Dew Point in Heating

An organic EL display unit was fabricated in the same manner as that ofExample 1, except that the dew point in the heating step after formingthe hole transport layer 16BB of the blue organic EL device 10Bdescribed in Example 1 was changed to −80 degrees centigrade in Example10, −70 degrees centigrade in Example 11, −50 degrees centigrade inExample 12, −40 degrees centigrade in Example 13, and −10 degreescentigrade in Example 14.

Examples 15 to 18 Influence of Oxygen Concentration in Heating

An organic EL display unit was fabricated in the same manner as that ofExample 1, except that the oxygen concentration in the heating stepafter forming the hole transport layer 16BB of the blue organic ELdevice 10B described in Example 1 was changed to 1000 ppm in Example 15,100 ppm in Example 16, 1 ppm in Example 17, and 0.1 ppm in Example 18.

Evaluation Result

For the obtained red, green, and blue organic EL devices of Examples 1to 18 and Comparative examples 1 and 2, drive voltage (v), currentefficiency (cd/A), and chromatic coordinate in driving at a currentdensity of 10 mA/cm² were measured. Further, time of luminance reductionby half in the case of constant current driving at a current density of100 mA/cm² was measured. The results are illustrated in Table 1 to Table5.

TABLE 1 Blue hole Blue Blue hole Blue hole transport light transporttransport layer: heating Light Hole emitting layer layer: layer: heatingenvironmental Drive Current Chromatic emitting transport (common heatingenvironmental oxygen voltage efficiency coordinate Acceleration Examplecolor layer layer) temperature dew point concentration (V) (Cd/A) (x, y)test T90 (h) Example 1 Red Compound 2 (20)/103 8.7 7.5 0.65, 0.32 340 h3 (1) Green Compound 7.8 7.8 0.20, 0.68 280 h 3 (1) Blue Compound 5.37.3 0.15, 0.15 240 h 1 (56) Comparative Red Compound 2 (20)/103 8.7 7.50.65, 0.32 340 h example 1 3(1) Green Compound 7.8 7.8 0.20, 0.68 280 h3 (1) Blue Compound 6.4 3.2 0.15, 0.15  40 h 3 (1) Comparative RedCompound 2 (20)/103 8.9 7.0 0.65, 0.32 300 h example 2 3 (2) GreenCompound 8.0 7.2 0.20, 0.69 270 h 3 (2) Blue Compound 7.2 4.6 0.18, 0.19 50 h 3 (2)

As evidenced by Table 1, in Example 1 in which the hole transport layer16BB of the blue organic EL device 10B was formed by coating of the lowmolecular material, both current efficiency and life of blue were moreimproved than in Comparative examples 1 and 2 in which the polymermaterial was used. Meanwhile, in Comparative examples 1 and 2, currentefficiency and life of blue were significantly inferior to currentefficiency and life of the other colors.

TABLE 2 Blue Blue hole light Blue hole Blue hole transport emittingtransport transport layer: heating Light Hole layer layer: layer:heating environmental Current Chromatic emitting transport (commonheating environmental oxygen Drive voltage efficiency coordinateAcceleration Example color layer layer) temperature dew pointconcentration (V) (Cd/A) (x, y) test T90 (h) Example 1 Blue Compound 2(20)/103 100 deg C. −60 deg C. 10 ppm 5.3 7.3 0.15, 0.15 240 h 1 (56)Example 2 Blue Compound 5.3 7.2 0.15, 0.15 230 h 1 (58) Example 3 BlueCompound 5.6 7.1 0.15, 0.15 200 h 1 (22) Example 4 Blue Compound 5.2 7.60.15, 0.15 260 h 1 (23)

As evidenced by Table 2, in Example 1 in which the compound 1(56) wasused as a low molecular material of the hole transport layer 16BB of theblue organic EL device 10B, in Example 2 in which the compound 1(58) wasused as a low molecular material of the hole transport layer 16BB of theblue organic EL device 10B, in Example 3 in which the compound 1(22) wasused as a low molecular material of the hole transport layer 16BB of theblue organic EL device 10B, and in Example 4 in which the compound 1(23)was used as a low molecular material of the hole transport layer 16BB ofthe blue organic EL device 10B, current efficiency and life of blueshowed high performance.

FIG. 14 and FIG. 15 respectively illustrate results obtained byexamining light emitting spectrum and life for the blue organic ELdevices of Example 2 and Comparative example 1. As evidenced by FIG. 14and FIG. 15, in Example 2 in which the hole transport layer 16BB of theblue organic EL device 10B was made of the low molecular material, boththe peak intensity of the light emitting spectrum and the life of bluewere significantly improved compared to those in Comparative example 1in which the polymer material was used.

In other words, it was found that in the case where the hole transportlayer 16BB of the blue organic EL device 10B was formed by coating ofthe low molecular material, both light emitting efficiency and life ofblue were able to be improved.

TABLE 3 Blue Blue hole light Blue hole Blue hole transport emittingtransport transport layer: heating Light Hole layer layer: layer:heating environmental Current Chromatic emitting transport (commonheating environmental oxygen Drive voltage efficiency coordinateAcceleration Example color layer layer) temperature dew pointconcentration (V) (Cd/A) (x, y) test T90 (h) Example 5 Blue Compound 2(20)/103  50 deg C. −60 deg C. 10 ppm 5.4 6.2 0.15, 0.15 180 h Example 6Blue 1 (56)  80 deg C. 5.3 7.3 0.15, 0.15 220 h Example 1 Blue 100 degC. 5.3 7.3 0.15, 0.15 240 h Example 7 Blue 130 deg C. 5.3 7.2 0.15, 0.15240 h Example 8 Blue 150 deg C. 5.8 6.5 0.15, 0.15 150 h Example 9 Blue180 deg C. 6.8 2.1 0.23, 0.20  10 h

Table 3 illustrates results obtained by changing heating temperature inthe heating step after coating the hole transport layer 16BB of the blueorganic EL device 10B. As evidenced by Table 3, as temperature wasincreased from 50 degrees centigrade, current efficiency and life wereimproved. Meanwhile, in Example 9 in which temperature was increased upto 180 degrees centigrade, increase of drive voltage, decrease ofcurrent efficiency, and drastic reduction of life were shown. In otherwords, it was found that in the case where the heating step is performedat temperature from 50 degrees centigrade to 150 degrees centigrade bothinclusive, current efficiency and life of blue were able to be improved.

TABLE 4 Blue Blue hole light Blue hole Blue hole transport emittingtransport transport layer: heating Light Hole layer layer: layer:heating environmental Current Chromatic emitting transport (commonheating environmental oxygen Drive voltage efficiency coordinateAcceleration Example color layer layer) temperature dew pointconcentration (V) (Cd/A) (x, y) test T90 (h) Example Blue Compound 2(20)/103 100 deg C. −80 deg C. 10 ppm 5.3 7.3 0.15, 0.15 240 h 10 1 (56)Example Blue −70 deg C. 5.3 7.3 0.15, 0.15 245 h 11 Example 1 Blue −60deg C. 5.3 7.3 0.15, 0.15 240 h Example Blue −50 deg C. 5.3 7.1 0.15,0.15 220 h 12 Example Blue −40 deg C. 5.8 6.5 0.15, 0.15 200 h 13Example Blue −10 deg C. 7.2 5.4 0.23, 0.20 150 h 14

Table 4 illustrates results obtained by changing atmosphere dew point inthe heating step after coating the hole transport layer 16BB of the blueorganic EL device 10B. As evidenced by Table 4, significant change ofefficiency and life was not shown until about −40 degrees centigrade,but slight reduction of current efficiency and life was confirmed atabout −10 degrees centigrade. In other words, it was found that in thecase where the atmosphere dew point was from −80 degrees centigrade to−40 degrees centigrade both inclusive, current efficiency and life ofblue were able to be improved.

TABLE 5 Blue Blue hole light Blue hole Blue hole transport emittingtransport transport layer: heating Light Hole layer layer: layer:heating environmental Current Chromatic emitting transport (commonheating environmental oxygen Drive voltage efficiency coordinateAcceleration Example color layer layer) temperature dew pointconcentration (V) (Cd/A) (x, y) test T90 (h) Example Blue Compound 2(20)/103 100 deg C. −60 deg C. 1000 ppm 7.9 5 0.15, 0.15  90 h 15 1 (56)Example Blue  100 pm 6 6.9 0.15, 0.15 100 h 16 Example 1 Blue  10 ppm5.3 7.3 0.15, 0.15 240 h Example Blue   1 ppm 5.2 7.3 0.15, 0.15 240 h17 Example Blue   0.1 ppm 5.2 7.4 0.15, 0.15 245 h 18

Table 5 illustrates results obtained by changing atmosphere oxygenconcentration in the heating step after coating the hole transport layer16BB of the blue organic EL device 10B. As evidenced by Table 5, as theoxygen concentration was 100 ppm or more, decrease of current efficiencyand reduction of life were confirmed. In other words, it was found thatin the case where the atmosphere oxygen concentration was from 0.1 ppmto 100 ppm both inclusive, current efficiency and life of blue were ableto be improved. Further, it was found that the atmosphere oxygenconcentration was more preferably from 0.1 ppm to 10 ppm both inclusive.

While the present application has been described with reference to theembodiment and the examples, the present application is not limited tothe foregoing embodiment and the foregoing examples, and variousmodifications may be made.

For example, the material, the thickness, the film-forming method, thefilm-forming conditions and the like of each layer are not limited tothose described in the foregoing embodiment and the foregoing examples,but other material, other thickness, other film-forming method, andother film-forming conditions may be adopted.

Further, in the foregoing embodiment and the foregoing examples, thedescription has been specifically given of the structures of the organicEL devices 10R, 10G, and 10B. However, it is not always necessary toprovide all layers, and other layer may be further provided.

Further, in the foregoing embodiment, the description has been given ofthe active matrix display unit. However, the present application is ableto be also applied to a passive matrix display unit. Furthermore, thestructure of the pixel drive circuit for driving the active matrix isnot limited to the structure described in the foregoing embodiment. Ifnecessary, a capacity device or a transistor may be added. In this case,according to the change of the pixel drive circuit, a necessary drivecircuit may be added in addition to the foregoing signal line drivecircuit 120 and the foregoing scanning line drive circuit 130.

It should be understood that various changes and modifications to thepresently preferred embodiments described herein will be apparent tothose skilled in the art. Such changes and modifications can be madewithout departing from the spirit and scope of the present subjectmatter and without diminishing its intended advantages. It is thereforeintended that such changes and modifications be covered by the appendedclaims.

The invention claimed is:
 1. An organic EL display unit comprising: alower electrode provided respectively for a red organic EL device, agreen organic EL device, and a blue organic EL device on a substrate; ahole injection layer provided respectively for the red organic ELdevice, the green organic EL device, and the blue organic EL device onthe lower electrode; a hole transport layer made of a polymer materialprovided respectively for the red organic EL device and the greenorganic EL device on the hole injection layer; a red light emittinglayer made of a polymer material provided on the hole transport layerfor the red organic EL device; a green light emitting layer made of apolymer material provided on the hole transport layer for the greenorganic EL device; a hole transport layer made of a low molecularmaterial provided on the hole injection layer of the blue organic ELdevice; a blue light emitting layer made of a low molecular materialprovided on the whole area of the red light emitting layer, the greenlight emitting layer, and the hole transport layer for the blue organicEL device; and an electron transport layer, an electron injection layer,and an upper electrode sequentially provided on the whole area of theblue light emitting layer, wherein the hole transport layer for the blueorganic EL device is formed by an evaporation method and the holetransport layers for the red and green organic EL devices are formed bya coating method or a printing method, and wherein the hole transportlayer of the blue organic EL device is made of an organic materialexpressed by General formula 1 shown in Chemical formula 3:

where A1 to A3 in the General formula 1 respectively and independentlyrepresent a substituted or unsubstituted aryl group or a substituted orunsubstituted heterocyclic group.
 2. The organic EL display unitaccording to claim 1, wherein the blue light emitting layer is made of acompound expressed by General formula 2 shown in Chemical formula 4:

where R1 to R6 in General formula 2 respectively and independentlyrepresent hydrogen, halogen, a hydroxyl group, a substituted orunsubstituted carbonyl group having 20 or less carbon atoms, asubstituted or unsubstituted carbonylester group having 20 or lesscarbon atoms, a substituted or unsubstituted alkyl group having 20 orless carbon atoms, a substituted or unsubstituted alkenyl group having20 or less carbon atoms, a substituted or unsubstituted alkoxyl grouphaving 20 or less carbon atoms, a cyano group, a nitro group, asubstituted or unsubstituted silyl group having 30 or less carbon atoms,a substituted or unsubstituted aryl group having 30 or less carbonatoms, a substituted or unsubstituted heterocyclic group having 30 orless carbon atoms, or a substituted or unsubstituted amino group having30 or less carbon atoms.
 3. The organic EL display unit according toclaim 2, wherein the hole injection layer is made of at least one of apolyaniline and oligoaniline material.
 4. An organic EL display unitcomprising: a lower electrode provided respectively for a red organic ELdevice, a green organic EL device, and a blue organic EL device on asubstrate; a hole injection layer provided respectively for the redorganic EL device, the green organic EL device, and the blue organic ELdevice on the lower electrode; a hole transport layer made of a polymermaterial provided respectively for the red organic EL device and thegreen organic EL device on the hole injection layer; a red lightemitting layer made of a polymer material provided on the hole transportlayer for the red organic EL device; a green light emitting layer madeof a polymer material provided on the hole transport layer for the greenorganic EL device; a hole transport layer made of a low molecularmaterial provided on the hole injection layer of the blue organic ELdevice, the material of the hole transport layer for the blue organic ELdevice being different than materials of the hole transport layer of thered organic EL device and the hole transport layer of the green organicEL device; a blue light emitting layer made of a low molecular materialprovided on the whole area of the red light emitting layer, the greenlight emitting layer, and the hole transport layer for the blue organicEL device; and an electron transport layer, an electron injection layer,and an upper electrode sequentially provided on the whole area of theblue light emitting layer.
 5. An organic EL display unit comprising: alower electrode provided respectively for a red organic EL device, agreen organic EL device, and a blue organic EL device on a substrate; ahole injection layer provided respectively for the red organic ELdevice, the green organic EL device, and the blue organic EL device onthe lower electrode; a hole transport layer made of a polymer materialprovided respectively for the red organic EL device and the greenorganic EL device on the hole injection layer; a red light emittinglayer made of a polymer material provided on the hole transport layerfor the red organic EL device; a green light emitting layer made of apolymer material provided on the hole transport layer for the greenorganic EL device; a hole transport layer made of a low molecularmaterial provided on the hole injection layer of the blue organic ELdevice; a blue light emitting layer made of a low molecular materialprovided on the whole area of the red light emitting layer, the greenlight emitting layer, and the hole transport layer for the blue organicEL device; and an electron transport layer, an electron injection layer,and an upper electrode sequentially provided on the whole area of theblue light emitting layer, wherein the hole transport layer of the blueorganic EL device is made of an organic material expressed by Generalformula 1 shown in Chemical formula 3:

where A1 to A3 in the General formula 1 respectively and independentlyrepresent a substituted or unsubstituted aryl group or a substituted orunsubstituted heterocyclic group.